1. Technical Field
The present disclosure relates to LEDs, and particularly, to a driving circuit and a LED backlight module using the same.
2. Description of Related Art
Generally, a driving circuit is used in a LED backlight module for driving LEDs. A constant reference voltage equal to 0.6V or 0.8V is often provided in the driving circuit. The reference voltage is outputted to a voltage comparator to be compared with a sample voltage, thus, the currents of the LEDs can be adjusted to be constant according to the comparing result. In another aspect, the driving circuit may further include a constant current source for providing a current to each LED. The current can be changed to adjust a brightness of each LED. However, since the reference voltage remains unchanged and thus causes a bias voltage of a MOS transistor to remain unchanged, therefore, a certain amount of power consumption is generated when the current flows through other parts of the driving circuit. For example, when the reference voltage is equal to 0.8V and the current flows through the driving circuit is equal to 960 mA, the power consumption in the driving circuit may reach 0.768 W, which is converted to heat generated by the driving circuit. Due to the small size of the driving circuit, the heat may influence the driving circuit a lot to influence the performance and lifetime of the driving circuit.